From highly graphitic to amorphous carbon dots: a critical review

Abstract

The emergence of carbogenic nanoparticles (C-dots) as a new class of photoluminescent (PL) nanoemitters is directly related to their economical preparation, non-toxic nature, versatility and tuneability. C-dots are typically prepared by pyrolytic or oxidative treatment of suitable precursors. While the surface functionalities critically affect the dispesrsibility and the emission intensity of C-dots in a given environment, it is the nature of the carbogenic core that actually imparts their intrinsic PL properties. Depending on the synthetic approach and the starting materials, the structure of the carbogenic core can vary from highly graphitic all the way to completely amorphous. This critical review focuses on correlating the functions of C-dots with the graphitic or amorphous nature of their carbogenic cores. The systematic classification on that basis can provide insights on the origins of their intriguing photophysical behaviour and can contribute in realising their full potential in challenging applications.